CVE-2026-106437 Out-of-bounds read and write via undersized BSON buffer reservation in MongoDB C Driver

What is CVE-2026-106437?

CVE-2026-106437 is a medium-severity vulnerability in MongoDB C Driver, published on 8 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

The BSON buffer-reservation API in the MongoDB C Driver can record a length smaller than the five-byte BSON minimum. Later append or comparison operations can underflow unsigned length calculations and read or write outside the document buffer. An actor who can influence the length supplied by an embedding application can cause the application to terminate or read or corrupt adjacent process memory. Reaching this issue requires the application to pass an undersized value to bson_reserve_buffer and then perform an affected operation.

Weakness: CWE-191

Which versions are affected by CVE-2026-106437?

It affects 1 product.

Products include Mongodb C Driver.

How do I fix CVE-2026-106437?

Apply the vendor's patch.

Is CVE-2026-106437 being exploited?

There is no known exploitation of CVE-2026-106437 in the wild and no public exploit code.

Other vulnerabilities in MongoDB C Driver

• CVE-2026-93393 Heap overflow via oversized decrypted TLS record sequence in Windows Secure Channel stream Critical 9.2
• CVE-2026-6691 MongoDB C Driver Cyrus SASL Canonicalization Buffer Overflow High 8.6
• CVE-2026-84964 Heap corruption via OCSP request double free from crafted multi-URL certificate in TLS client High 8.2
• CVE-2024-7553 Accessing Untrusted Directory May Allow Local Privilege Escalation High 7.3
• CVE-2026-93395 Integer Underflow → Heap Out-of-Bounds Read in `bson_new_from_buffer() Medium 6.9

Sources

• CVE record
• NVD
• OSV
• How this page is made

Also known as DEBIAN-CVE-2026-106437, UBUNTU-CVE-2026-106437.